Stocks are closing slightly lower Friday as the market's eight-week winning streak comes to an end, the AP reports. Companies that make medical devices and health care equipment declined after an analyst said Amazon may shake up their industry over the next few years. Medtronic fell 1.8% and Baxter International fell 2.1%. Stocks finished lower for the second day in a row. That hadn't happened in a month. Retailers climbed. JC Penney jumped 15.3% after it said a key sales measurement improved. The Standard & Poor's 500 index fell 2 points, or 0.1%, to 2,582. The Dow Jones industrial average declined 39 points, or 0.2%, to 23,422. The Nasdaq composite index was nearly unchanged at 6,750. (More stock market stories.)